hwmon: (pmbus/mp2975) Fix PGOOD in READ_STATUS_WORD

MP2973 & MP2971 return PGOOD instead of PB_STATUS_POWER_GOOD_N.
Fix that in the read_word_data hook.

MP2975 should not be affected, but that has not been confirmed with
hardware.
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Signed-off-by: Naresh Solanki <Naresh.Solanki@9elements.com>
Link: https://lore.kernel.org/r/20230731092204.2933045-1-Naresh.Solanki@9elements.com
[groeck: Rephrased description to indicate that MP2975 is likely not affected]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

drivers/hwmon/pmbus/mp2975.c

@@ -380,6 +380,11 @@ static int mp2975_read_word_data(struct i2c_client *client, int page,
 	int ret;
 
 	switch (reg) {
+	case PMBUS_STATUS_WORD:
+		/* MP2973 & MP2971 return PGOOD instead of PB_STATUS_POWER_GOOD_N. */
+		ret = pmbus_read_word_data(client, page, phase, reg);
+		ret ^= PB_STATUS_POWER_GOOD_N;
+		break;
 	case PMBUS_OT_FAULT_LIMIT:
 		ret = mp2975_read_word_helper(client, page, phase, reg,
 					      GENMASK(7, 0));